Apparatus for the production of etched copper printing cylinders



y 1936- H. KINDERMANN 2,049,012

APPARATUS FOR THE PRODUCTION OF ETCHED COPPER PRINTING CYLINDERS Original Filed Jan. 26; 1934 3nnentor:

attorney Patented July 28, 1936 APPARATUS FOR, PRODUCTION OF ETCHED COPPER PRINTING CYLINDERS Hermann Kindermann, Koniginhof,

- Czechoslovakia Original application January 26, 1934, Serial No.

Divided and this application July 6,

1935, Serial No. 30,176. In Germany February 1 Claim.

This is a division of application of Hermann Kindermann, Serial No. 708,496, filed January 26, 1934 and the invention relates to an apparatus for,producing etching grounds on copper 5 rollers for texile printing by direct reprint without reversing. There are various methods which render it possible to produce upon copper rollers an etching ground, by the aid of which the rollers can bedeeply etched to a pattern. The oldest known process for textile printing consists in scratching the pattern right onto the copper by hand in a roller that has been coated with an etch-proof varnish. Modern processes make use in addition of the help of a pantograph or of electrically actuated scratching devices.

According to other processes, the etching ground is made by copying by means of films, either directly upon a layer which gives the g etching groundafter exposure and development,

or else upon layers which are only converted into the actual etching ground by further treat-' vment.

Other processes are based upon impressing those parts of a design which are subsequently to be deepened by etching, upon the copper roller by offset printing. For this, of course, a reversal of the printing image upon the roller is necessary, quite apart from the fact that in this process the cutting of the pattern has to be effected not in the most advantageous line given by the guide marks, but as nearly as possible along a generating line of the copper roller, or that in the case of the cutting according to the guide marks a portion of the grease ink is transferred back from the copper roller to the offset roller, so that at these positions there is less grease ink upon the copper roller. This phenomenon frequently makes itself perceptible in the ensuing reversal, in the form of faults.

In the case of the hand engravingprocesses and the mechanical and electrical pantographs hereinbefore mentioned, the employment of autotype and similar lenticular screens is preeluded, since these processes can only work with stroke elements and not with point elements? The remaining processes mentioned involve, for the arranging of the individual elements in series, the use of expensive adding machines. Rouleaux printing rollers need in comparison very deep engraving, and consequently the processes for the production of such rollershitherto taken over from the technique of reproduction exhibit various-defects, particularly with respect to the etching ground.

It has now been found that the very powerful etching grounds needed for Rouleaux printing rollers can be obtained by proceeding in such a way that the etching ground is only reprinted in the form of broad margins, and the remain- 5 ing surfaces are afterwards covered by hand.

An important novel feature of this process consists in the fact that it can be carried out by suitably constructed apparatus, which is de scribed below, withthe retouching process 10 known in lithography. It-must therefore be regarded as a special advantage that the production of the necessary grease prints on the reprinting paper can be efiected by any desired process, such as lithography, letterpress print- 15 ing, zincography or the like.

The invention herein described and claimed consists in suitably constructed apparatus for carrying out the improved process just described and is illustrated by way of example in the ac- 20 companying drawing, in which:

Figure 1 shows in front elevation the means for actuating the lower cylinder of ,the apparatus with the track shown in section;

Fig. 2 is a diagrammatic view showing the rela- 5- tion of the various parts; and

Fig. 3 shows the apparatus in front elevation. The machinethat has been devised for the carrying out of this process consists essentially of an underframe D, upon which are located 30 three bent standards or plummer blocks L, and

L1, L2. The plummer blocks L1 and L2 support a copper roller or cylinder K, mounted upon a shaft or spindle Sp. A roller G, covered with indiarubber, serves as a counter-pressure roll. The 35 pressing of the indiarubber cylinder, G against the copper cylinder K is efiected by means of toothed racks Z1, and Z2, which are combined in bobbin-shaped slewing ball bearings KL, which 50 rolh upon rails Sch. Each of these rails Sch is formed with a slot SL near the working position of the cylinder G, so that the" forked ends Ga of the racks Z1 and Z2 can raise the bearingsKh and thus press the cylinder G against 55 the copper cylinder K. The forks Ga are made so wide that the above-mentioned troughs placed upon them can be raised and lowered. The tympan sheet rests upon the top 0 of a table,

which is preferably so adjusted that the upper surface of the top 0 always. lies approximately in the upper tangential plane of the indiarubber cylinder G. This result is best attained if the table can be raised and lowered simultaneously with the roller G by actuating the racks Z1 and Z2. The tabletop O is readily removable, in order to render the copper roller freely accessible for machining. The machine is reversibly driven by an electric motor, through the medium of stepped pulleys or speed cones A.

The transferring to the copper roller prefably proceeds in such a way that the work of retouching is already effected upon the table top 0. The indiarubber cylinder G is moved into its operative position underneath the copper roller K, and is located from 2 to 3 centimetres below the latter. Through this gap 2 or 3 centimetres wide the tympan sheet is introduced; and it is to be noted that when this sheet is pressed against the copper roller by the cylinder G, which now takes place, normally no etching ground elements are to come into contact with the copper roller.

When the rollers K and G are under pressure the tympan sheet is now rotated so far between the two cylinders K and G, by pulling with the hand on the counter-shaft belt, that all the transfer papers are lifted off the sheet and adhere to the copper roller K. After-the pressure between the cylinders K and G has been discontinued, the tympan sheet and the table top 0 are removed, and steps are taken for pulling the transfer papers off the copper cylinder. This is done by renewed pressing of the indiarubber cylinder G according to the nature of the transfer paper, with simultaneous or alternate moistening of the transfer papers, or by letting the copper roller rotate into a trough filled with water placed underneath.

The etching ground transferred in this way to the copper cylinder is reinforced by dusting with asphalt, resin or the like and melting this applied substance, for the purpose of obtaininggreater power to resist the etching liquids.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:-

Apparatus for carrying out the process of the character described by the aid of reprinting papers by the tympan or retouching process, including a copper rol1er,.a reprinting roller arranged undcrncath the copper roller, forks for raising and lowering the reprinting roller, rails on which the said reprinting roller is capable of being moved out thereon, and the rails being formed with apertures for the forks serving for raising and lowering of the reprinting roller.

HERMANN KINDERMANN. 

